Environmental enrichment of laboratory animals used in regulatory toxicology studies (1999)

Dean, S. W.

Abstract

This paper attempts to review the various methods of enrichment through social contact, enhancement of the environment and diet, and improvements in husbandry ... within the context of a laboratory which conducts regulatory toxicology. ... A creative approach to environmental enrichment is indeed compatible with regulatory toxicology. It is hoped that this will encourage those responsible for the care and welfare of animals in such a laboratory to challenge historical practices and include environmental enrichment as a fundamental necessity of study design. ... Another hurdle to overcome is that of historical data, and the concept that any changes to the way in which studies are performed will in some way invalidate the precious historic database. ...If we tailor our approach to accommodate the needs of good science, this will inevitably equate to good animal welfare.An earlier failure was experienced with pair housing in a study where [an unspecified number of] mature [long-tailed] males, which had been paired for many months with no problems, had to be separated for 28 days. When these animals were returned [presumably without brief prior noncontact introduction to assure proper recognition of companions] to their original pairings they were no longer compatible, leading to permanent single housing thereafter. ... The assumption that certain regulatory authorities 'prefer' single-housing should be challenged. ... Group housing should become the norm whenever animals are compatible, and anything less should be justified on the basis of sound science.